Continuous strips or assemblies of pre-opened bags connected together are well known in the packaging art and provide the end user with an alternative to stacks of individual bags. The continuous strip assemblies are attractive for many packaging operations since they can be fed through various types of automatic packaging machines for filling and final sealing while in strip form and thereafter separated into individual filled bags. The continuous strips of bags are generally flattened tube-like assemblies having two layers of flexible packaging material appropriately sealed or joined together to define individual bags in the assembly that have front and rear walls, closed sides, a closed end and an open end through which the bags can be filled. The open end is sealed to form an enclosure for the packaged articles or product after filling. Individual bags are separated from the strips after being filled and sealed or concurrently with the filling and final sealing operation. The strips are made of heat sealable flexible packaging material, such as plastic films, sealable foil laminates and/or sealable paper packaging materials.
Two general constructions of pre-opened bags connected together in strips or assemblies are known in the art. One construction consists of a strip of pre-opened bags in which the open end extends transversely of the strip through one wall of each bag. This type of construction is described in U.S. Pat. No. 3,254,828, issued on June 7, 1966 to H. Lerner, now expired. The second type of construction consists of interconnected bags that have an open end extending longitudinally of the strip. An assembly of this type is described in U.S. Pat. No. 3,791,573, issued on Feb. 12, 1974 to Titchenal et al. The strips of connected bags can be supplied to the end user in roll-form or in a fan-folded stack and can be unprinted or printed in one or more colors as desired by the end user. A strip can have any selected number of bags, such as on the order of several hundred to several thousand bags per strip, and the bags can be of any specific size required by the end user.
Heat sealing techniques, which are well known in the flexible packaging art, are used to form the strips described in the patents listed above. Heat sealing is also used to close a bag after it has been filled with the selected product or articles. This results in a sealed bag that can be opened only by rupturing a portion of the bag, such as by tearing or cutting, when the ultimate consumer seeks to remove the packaged articles from the bag. This not only destroys the integrity of the bag, but in many instances results in the bag being unusable if only part of the packaged contents is to be removed when first opened.
Our present invention was developed to provide continuous strips of pre-opened bags of the foregoing type that can be reclosed after being first opened, thereby providing a bag that functions as a packaging enclosure for the articles or product remaining in the bag after some have been removed. Another objective of our invention is to provide strips of pre-opened reclosable bags that can be made with the bag making machinery commercially available from a number of companies, both in the U.S. and other countries, so that the constructions of the invention can be made without modifying the machines other than adding minor elements that can be easily installed on existing bag making machines. A further principal object of our invention is to provide pre-opened reclosable bags in the form of continuous strips that can be filled, sealed and separated into individual filled bags using automatic packaging machinery of the type now commonly available and in general use. Another principal objective of our invention is to develop strips of pre-opened reclosable bags in which individual filled bags separated from the strips are structurally altered when first opened to thereby provide a tamper-proof bag in that evidence of the first opening will be visually apparent. These and other objectives of the invention will become apparent from the detailed description that is presented below.